1,4-Dioxane: Occupational Exposure Considerations

I. Federal Requirements and Recommendations

The Occupational Health and Safety Administration (OSHA) governs worker safety, including exposure to 1,4-dioxane. OSHA established a research organization called the National Institute for Occupational Safety and Health (NIOSH), which created the occupational exposure standard for 1,4-dioxane.  NIOSH and OSHA published an additional document that also discusses workplace exposure to 1,4-dioxane.  As a note, NIOSH’s current guidance contains more protective levels than does OSHA’s enforceable levels.

The following table summarizes the requirements and recommendations for occupational exposure inhalation to 1,4-dioxane:

There are several documents available that, in part, discuss occupational safety regarding 1,4-dioxane:

• NIOSH’s Pocket Guide to Chemical Hazards;
• OSHA’s Chemical Database;
• EPA’s 1,4-dioxane Document;
• EPA’s Technical Fact Sheet;
• EPA’s Scope of the Risk Evaluation (expand the document using the lower left-hand corner);
• EPA’s Final Risk Evaluation (December 2020), but numerous state entities have challenged the findings in court (March 2021); and
• ACGIH’s Informational Sheet.

II. State Requirements and Recommendations

Many states have issued regulations or guidance to protect workers potentially exposed to 1,4-dioxane.  California OSHA has established a Permissible Exposure Limit for 1,4-dioxane of 0.28 ppm averaged over an eight hour shift (or, approximately one-third of OSHA’s exposure limit, making California’s standard more stringent).

The following are the relevant information sheets published by the states:

• California (CA Office of Environmental Health Human Assessment);
• Connecticut (CT Department of Energy and Environmental Protection);
• Florida (FL Department of Health);
• Massachusetts (MA Department of Environmental Protection);
• Michigan (MI Department of Health and Human Services);
• New Hampshire (NH Department of Environmental Services);
• New Jersey (NJ Department of Health and Human Services);
• New York (NY Human Health Fact Sheet);
• North Carolina – Cape Fear River Basin (NC Environmental Quality);
• Vermont (VT Department of Health); and
• Wisconsin (WI Department of Health Services).

Several other states, cities, and counties have published information to address 1,4-dioxane in drinking water supplies.  Minnesota Department of Health provides a helpful example.

III. Conclusion

We anticipate that regulation of occupational safety concerns for 1,4-dioxane at the federal and state levels will continue in the future.  If you have any questions regarding 1,4-dioxane, please contact Phil Karmel (212-541-2311), John Kindschuh (314-259-2313), or Erin Brooks (314-259-2393).

¹OSHA also states that 1,4-dioxane may be absorbed through the skin.